Paper strengthening resins are sold commercially as aqueous solutions. Commonly such resins are thermosetting, polymeric reaction products of epichlorohydrin and a polyamide derived from a polyalkylene polyamine and certain dicarboxylic acids. U.S. Pat. No. 2,926,154 to Keim describes aqueous solutions of such resins. Typically aqueous solutions of such resins contain an amine curing accelerator such as ethylenediamine or diethylenetriamine. Such compositions are disclosed in Espy U.S. Pat. No. 3,442,754. The presence of the accelerator makes it possible to thermally set the resin in a shorter time.
Commercially such aqueous solutions usually contain about 10 to 35% by weight resin. Most of the remaining portion of the solution is water. Because such solutions. Such aqueous solutions have a limited shelf-life.
It is an object of the present invention to provide a dry form of paper strengthening resin that may be shipped in this form, and dissolved at the site where it is to be used. Such dry compositions have a very long shelf-life.